Relay configuration for an electro-pneumatic train

ABSTRACT

A relay valve configuration which can be used with various cars in an electropneumatic train and under the control of one of the electropneumatic brake control valves. The improved brake control valve includes a relay valve mounted at an interface of the manifold. The valve has a source inlet connected to the reservoir interface port, an inlet connected to atmosphere, an outlet connected to the brake cylinder interface port and a control inlet connected to the exhaust interface port. The valve is responsive to the control inlet connected to the exhaust interface port to selectively connect the brake cylinder interface port either to the reservoir interface port or atmosphere. The exhaust interface port in AAR is known as the retainer port. A check valve/choke is also mounted on the manifold of the interface and is in the same housing as the relay valve.

CROSS REFERENCE

This application is a divisional and claims priority to U.S. patentapplication Ser. No. 11/020,120 filed Dec. 27, 2004.

BACKGROUND AND SUMMARY OF THE DISCLOSURE

The present invention relates generally to electropneumatic (“EP”) brakecontrol valves and, more specifically, to a relay valve for use in anelectropneumatic train.

Electropneumatic brake control valves are well known in the passengerrailroad art and the mass transit railroad art. Because the trains areshort and are not involved generally in a mix and match at aninterchange of different equipment, the ability to provide pneumatic andelectrical control throughout the train has been readily available inthe passenger and the mass transit systems. In freight trains, thetrains may involve as much as 100 cars stretching over one mile or more.The individual cars may lay idle in harsh environments for up to a yearwithout use. Also, because of the long distance they travel, the carsare continuously moved from one consist to another as it travels to itsdestination. Thus, the use of electropneumatic-pneumatic valves in thefreight trains has been very limited.

Recently, the American Association of Railroads (“AAR”) has been testingand experimenting with the incorporation of electropneumatic valves onthe cars of a freight train. Various systems exist in the industry foradaptation of existing pneumatic brake control valves, as well asstandalone electropneumatic brake control valves.

An example of an adaptation of a standard AAR brake control valve isillustrated in U.S. Pat. No. 5,393,129 to Troiani et al. Troiani et al.provides an overlay at the connection of the pneumatic system to thepipe bracket. An electropneumatic valve system is connected to theemergency reservoir between the retainer port of the pipe bracket andthe retainer. The service valve portion remains in its release position,which allows transmission of the brake control signal from theelectropneumatic brake control valve through the service portion to thebrake cylinder.

Various configurations of electropneumatic brake control valves mountedto a standard pipe bracket are illustrated in U.S. Pat. No. 6,325,464 toTruglio et al.

Although the technology for electropneumatic brake control valves hasbeen implemented and accepted, there is still a cost factor ininstalling an electropneumatic-controlled device on each railroad car.

The present disclosure provides a relay valve configuration as apneumatic brake control valve which can be used with various cars in anelectropneumatic train and under the control of one of theelectropneumatic brake control valves. This reduces the number ofelectropneumatic brake control valves. The improved brake control valveincludes a relay valve mounted at an interface of the manifold. Thevalve has a source inlet connected to the reservoir interface port, aninlet connected to atmosphere, an outlet connected to the brake cylinderinterface port and a control inlet connected to the exhaust interfaceport. The valve is responsive to the control inlet connected to theexhaust interface port to selectively connect the brake cylinderinterface port either to the reservoir interface port or atmosphere. Theexhaust interface port in AAR is known as the retainer port. A checkvalve/choke is also mounted on the manifold at the interface and is inthe same housing as the relay valve.

Also, connected to the manifold is a bypass plate or a vent valvestructure, which includes a passage connecting the two brake cylinderports, which are normally used for the emergency brake portion.

In the brake system for a train, there are at least two brake controlvalves. At least one of the valves is the pneumatic brake control valve,including the relay valve previously described. A pipe connects thebrake cylinder port of the first brake control valve to the exhaust portof the second control valve so as to control the vent valve with thebrake cylinder pressure. The first brake control valve is anelectropneumatic brake control valve. The train may include a pluralityof brake control valves, including the vent valve previously described,and a single electropneumatic brake control valve can control more thanone of the second style brake control valve through its exhaust port.

These and other aspects of the present disclosure will become apparentfrom the following detailed description of the disclosure, whenconsidered in conjunction with accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an electropneumatic train incorporatingelectropneumatic and pneumatic brake control valves according to thepresent disclosure.

FIG. 2 is an example of an electropneumatic brake valve according to theprior art.

FIG. 3 is a schematic of the relay valve of FIG. 1.

FIG. 4 is a cross-sectional view of the relay valve of the schematic ofFIG. 3.

FIG. 5 is a schematic of an electropneumatic train incorporation pairsof electropneumatic and pneumatic brake control valves according to thepresent disclosure.

FIG. 6 is a schematic of an electropneumatic train incorporating anelectropneumatic brake control valve and a pair of pneumatic brakecontrol valves according to the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown in FIG. 1, two cars are interconnected by a brake pipe 14 andan electrical train line 50, which carries power and communicationsignals to the various electropneumatic brake control valves. Anadditional pipe 16 connects the first and second cars. As will bedescribed below, pipe 16 is either a new pipe or an existing pipe withinthe train. Various trains have a holding brake pipe, which is not usedin the present electropneumatic brake control systems and, therefore, isavailable. Each of the cars includes a standard manifold 30 connectedvia cut-off valve 12 to the brake pipe 14. A pair of reservoirs 22 arealso connected to the manifold 30, as is the brake cylinder 24. Thestandard inlet ports of the manifold 30 are brake pipe BP, brakecylinder BC, emergency reservoir ER, auxiliary reservoir AR and anexhaust/retainer port RET.

On car 1, an electropneumatic brake control valve 40 is mounted on theservice interface for the pipe bracket 30. These devices are known inthe industry as car control devices (“CCDs”). Mounted on the emergencyinterface is a vent valve 20.

Car 2, on its standard bracket 30, includes a relay valve 60. It mayalso include a vent valve 20, as illustrated in FIGS. 1 and 2, or mayinclude a bypass plate 70, as illustrated in FIG. 4. The relay valve 60,as shown below, is a pneumatic valve and not an electropneumatic valve.

Pipe 16 connects the brake cylinder port BC of the first car'selectropneumatic brake control valve to the exhaust or retainer port RETof the pneumatic brake control valve of the second car. As will bedescribed below, this is the control input to the relay valve 60. Inresponse to the control signal on port RET, the relay valve 60 connectsthe reservoir 22 or atmosphere to the brake cylinder 24 to control thebrakes on the second car. Thus, the pneumatic brake control valve of thesecond car is a pneumatic valve controlled by the electropneumatic valveof the first car.

Although only a single pair of brake control valves is illustrated inFIG. 1, the train may include a plurality of pairs of interconnectedelectropneumatic brake control valves and pneumatic brake control valvesas shown in FIG. 5. Also, a single electropneumatic brake control valvecan be connected to multiple pneumatic brake control valves having thestructure of the second car as shown in FIG. 6. This combination reducesthe cost in that a fewer number of electropneumatic brake control valvescan be used. Also, existing cars having only pneumatic brake controlvalves can be easily retrofitted with minimum change. The relay valve 60is mounted to the pipe bracket 30 without modification to the interfaceand uses existing studs and gaskets at the service portion interface ofthe standard pneumatic brake control valve. It should also be noted thateven though the vent valves 20 are shown mounted at the emergencyinterface, which is opposite the service interface, the emergency andservice interface may be on a common side known in the industry as asingle-sided bracket. As will be noted below, the relay valve 60includes a combination check valve and charging choke to allow the brakepipe 14 to charge the reservoirs 22.

The details of a CCD 40 of the prior art is illustrated in FIG. 2. Thisis from FIG. 2B of U.S. Pat. No. 6,325,464 and uses the same numbers.For details of the explanation of the operation, reference should bemade thereto, and it will not be explained in detail here. Thisstructure is also known as EP-60, which is available from New York AirBrake Corporation of Watertown, N.Y. The structure of vent valve 20 maybe that shown in U.S. Pat. No. 6,318,812 to Newton et al. This ventvalve is also available from New York Air Brake Corporation ofWatertown, N.Y. However, it should be noted that other vent valves maybe used or, as previously discussed with respect to the second car, thevent valve may just be a bypass plate, as illustrated in FIG. 4.

A schematic of the relay valve 60 is illustrated in FIG. 3. The relayvalve portion 600 includes a source input 602, atmospheric input 604, anoutput 606 and a control input or pilot input 608. The source input 602is connected by passage 612 to the emergency reservoir ER and theauxiliary reservoir AR. Passage 614 connects the atmospheric input 604to atmosphere ATM. The output 606 is connected by line 616 to the brakecylinder port BC. The pilot or control port 608 is connected to theexhaust or retainer port EXH/RET by passage 618. The output 606 is alsoconnected via passages 616 and 620 as a feedback to the relay valveportion 600 through restriction 622. The relay valve portion 600 isbiased by spring 610 to its release position illustrated in FIG. 3. Inthis position, the output 606 is connected to the atmosphere at input604.

Upon receipt of a brake signal at 608, the valve portion 600 moves downto the topmost position, wherein the emergency and auxiliary reservoirsare connected at 602 to the outlet 606. The pressure from the reservoirsis supplied through passage 616 to the brake cylinder port BC. It isalso fed back via passage 620 to the relay valve 600. Once the pressureat the brake cylinder BC reaches substantially that of the pilot signalat 608, the pressure at 620 and the spring 610 moves the valve portion600 to the middle lap position. In the lap position, the two inputs 602and 604 are disconnected from the output 606, which is now lapped orsealed. This holds the brake cylinder pressure.

Once the control signal is removed from 608, the relay valve 60 movesupward out of its lap position towards the release position. Theatmospheric input 604 is connected to the output 606, thereby connectingthe brake cylinder port BC to atmosphere. This releases the brake. Thisis a standard operation of a relay valve.

A passage 630 connects the brake pipe port BP to check valve/choke 632.Passages 634 and 636 connect the check valve/choke 632 to the emergencyand auxiliary reservoirs ER/AR. This allows charging of the reservoirsfrom the brake pipe. The relay valve 600 and the check valve/choke 632are all in a common housing of the relay valve 60. The relay valveportion 600 is equivalent to the BC valve in FIG. 2 of the prior art.

A specific implementation of the relay valve 60 is shown in FIG. 4. Thesame numbering is used as in the schematic of FIG. 3. The relay valveportion 600 may be the same relay valve portion used in the CCD 40 ofFIG. 1 and is connected to the interface ports ER, BC, BP, RET, AR atthe service interface. Also, illustrated is the bypass plate 70connecting the two brake cylinder ports on the emergency interface ofthe pipe bracket 30 to the brake cylinder port BC. Operation of therelay valves is well known, and a detailed explanation is not needed.

The manifold 30 may be any standard manifold (for example, an AB, ABD,ABDW, ABDX or a DB manifold). These are all interchangeable, as requiredby AAR. It should also be noted that even though this system has beendesigned for AAR railroads, it is equally applicable to non-AARcountries and standards.

Although the present disclosure has been described and illustrated indetail, it is to be clearly understood that this is done by way ofillustration and example only and is not to be taken by way oflimitation. The scope of the present disclosure is to be limited only bythe terms of the appended claims.

1. A brake system for a train comprising: at least first and secondbrake control valves; each brake control valve having a manifold whichincludes a brake pipe port, a reservoir port, and a brake cylinder portconnected respectively to a brake pipe, a corresponding reservoir and acorresponding brake cylinder; and a pipe fluidically connecting thebrake cylinder port of the first brake control valve's manifold to anexhaust port of the second control valve's manifold external to themanifolds.
 2. The brake system according to claim 1, wherein the firstbrake control valve is an electropneumatic brake control valve.
 3. Thebrake system according to claim 2, wherein the pipe connecting the brakecylinder port of the first brake control valve to the exhaust port ofthe second control valve is a hold brake pipe of the train.
 4. The brakesystem according to claim 2, including a third brake control valvesimilar to the second control valve and the exhaust port of the thirdcontrol valve is connected to the brake cylinder port of the first brakecontrol valve.
 5. The brake system according to claim 2, including aplurality of pairs of first and second brake control valves and theexhaust port of the second control valve of each pair is connected tothe brake cylinder port of the first brake control valve of that pair.6. The brake system according to claim 1, including a third brakecontrol valve similar to the second control valve and the exhaust portof the third control valve is connected to the brake cylinder port ofthe first brake control valve.
 7. The brake system according to claim 1,including a plurality of pairs of first and second brake control valvesand the exhaust poll of the second control valve of each pair isconnected to the brake cylinder port of the first brake control valve ofthat pair.
 8. The brake system according to claim 1, wherein at leastone of the first and second brake control valves includes a vent valvemounted to its manifold and responsive to pressure on the brake pipeport to vent the brake pipe.
 9. The brake system according to claim 1,wherein the first and second brake control valves are on adjacent carson the train.